Tonight, a story of sex, lies and videotape. And an almost deadly twist on that expression, now you see her, now you don't. As you're checking into hotels on vacation this summer, consider this -- what do those surveillance cameras really capture? Because tonight, it's going to take a modern day Sherlock Holmes, with a wild hunch, a Harley and a black leather jacket, to crack the mystery of the vanishing blond. It's a quiet, lonely place, a speck of grassy land around an undeveloped cul-de-sac on the outskirts of Miami. There's a "No dumping" sign in plain view but on the morning of February 21st 2sh, 2005, a utility worker passing by noticed that someone has ignored it in a big way. Curled up in the grass, a woman -- naked, unconscious and beaten within an inch of her life. The woman was airlifted to Jackson memorial hospital's rider trauma center in critical condition. Pretty much somebody dumped her out there. Reporter: To die? Yes. Reporter: So, it was pretty amazing that she was found alive. Absolutely. Reporter: Miami Dade detective Alan Foote caught the case of the mystery woman with no I.D. Well, I've got a Jane doe on my hands. She was beat up and cut up. She had cuts on her face. She had a swollen jaw, bruises on her body. Reporter: And unconscious. And unconscious. Reporter: At the crime scene, one potential clue -- a blue blanket. Police have it tested for trace evidence. It turns up nothing. They also canvass houses nearby. Tried to see if anybody noticed anything, and of course, we got no response there. I didn't see anything or heard anything. Reporter: As the news spreads -- There is no clothing, no license. Or anything that would distinguish who he is. Reporter: -- The mystery deepens. The victim remains unconscious until the following day. Then, the darkness recedes. I woke up. I had a lot of pain. I remember somebody ask me what was my name. Reporter: And what did you learn about her once she came to? She was able to write some information down on a piece of paper. Reporter: The petite mystery woman still can't speak but she's scrawled out some basic information. Her name is inn budnystka. She's from Ukraine. And she works for one of the many cruise lines that operate in Miami. I wanted to have an occupation in my life. I want to be someone. Reporter: That all makes sense. But what about this? Her attorney's name? Yes, her attorney's name. Reporter: Did that strike you as a little strange? Yes, it did. I did not know whether she was involved in something civil or something criminal. But for someone to ask for an attorney as a victim, right off the bat, does throw a red flag. Maybe they thought it was unusual that someone would ask for an attorney, but this woman had a horrific assault and probably was reaching for anything that she could. Reporter: Here's her story -- inn has been injured on the ship and has filed suit against the cruise line. That's why she had an attorney. Yes, I didn't know nobody. I was alone up here. So, the only one person who I knew that was my attorney. That was my lawyer. Reporter: While she was convalescing from her injury, inn is being housed by the cruise line at this hotel. The airport regency. About ten miles east of the vacant lot where she was found. The hotel would prove crucial to the mystery, especially its sophisticated security system. We have 16 cameras covering the whole perimeter of the hotel, including parking lot, the entrance, the exit, the lob bi, the restaurant, the lob bibar, the front desk, the back exits. Those cameras have motion sensor detector and then we have two security guards at night on duty. So, we can see, you know, anybody or anything that happens in the perimeter of the hotel. Reporter: For privacy reasons, the hotel does not have cameras in the elevators or the upstairs hallways. That would make a big difference later, but for now, detective Foote has this pile of DVDs from the first floor cameras to comb through. He begins scanning those recordings for any evidence of the crime. Where's the guard shack? Up here? It's here. Reporter: Back at the hospital, inn is eventually able to fill in some blanks about her whereabouts on the evening of the attack. She says she'd gone out with a friend that night to a restaurant in coconut grove. I had fun. We stayed there awhile. Had some drinks. Reporter: She remembers returning by taxi, alone shoshgtsly after midnight. But get this -- the security cameras catch her leaving again at 3:33 A.M. That's her in the red jacket. Seven minutes later, she's back at 3:40. Did that strike you as odd that she's going and coming in the middle of the night? I mean, she could explain that. Reporter: Inna recalls going to the gas station across the street to buy a phone card to call her mom back in Ukraine, which is seven hours ahead. I'm very close with my mother. And I used to call her very often back in Ukraine. Reporter: But here's where the case really turns into a mystery which could stump Sherlock Holmes. After returning from her errand, inn walks to the lobby elevators at 3:41 A.M. And is never seen by the hotel cameras again. The last we see of her. So, that's how we believe she was attacked in the hotel. Reporter: The next thing inn remembers is regaining consciousness for a brief moment in that vacant lot where she was found at 8:30 that morning. It was very cold, if I remember. It was, like, very, very cold. And dark. And cold. I couldn't stand up. And I could not walk. Reporter: But everything that happened in between the elevator and the cul-de-sac is a total blank. The memory was not clear because I was in pain, in too much pain. My head was not working absolutely. I was in shock. Reporter: The biggest mystery, of course, is, how did she get out of the hotel? Do you come up with any theories? I was looking for anything. Reporter: Police are confounded. They even inspect the landscaping below inna's fourth story room, on the offchance she might have been lowered or dropped from there. I am looking in her room over the balcony. I'm looking in the bushes to see if a body was thrown over and there was a -- a body imprint or a -- maybe she was lowered by rope. Reporter: That was kind of a long shot. Long shot. Reporter: A long shot that didn't pay off. No evidence of inn being lowered from the window. This case is a bona fide whodunit -- new questions and suspects popping up faster than any answers. Is the victim really a victim or was she somehow involved? And could someone from her personal life or the hotel staff be the missing key to the case? Did you accept that story? No, no. So, with that, he became my suspect.

This transcript has been automatically generated and may not be 100% accurate.

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